Do we have an obligation from preventing one wild plant or animal species from wiping out another? For instance, is it morally problematic to introduce to an ocean habitat an exotic species of fish which goes on to drive species to extinction? (Set aside the question of whether such a thing might also be problematic on, say, practical grounds.) Or do we simply say: "Well, the exotic fish have just as much a right to survive as the natives, so let's not worry if the former kill off the latter."